public class fuShu {

    public static void main(String[] args) {
        // 定义两个对象并赋值：c1(a+bi)=(2+4i),c2=(c+di)=(6+16i)
        Complex c1=new Complex();
        c1.real=2;
        c1.imaginary=4;
        Complex c2=new Complex();
        c2.real=6;
        c2.imaginary=16;

// 以字符串的方式输出：采用标准格式输出，即a+bi
        System.out.println("两个复数相加得："+c1.add(c2));

// 在每次调用并运算（此时real值发生变化）之后，再重新赋值：
        c1.real=2;
        c1.imaginary=4;

        System.out.println("两个复数相减得："+c1.sub(c2));
        c1.real=2;
        c1.imaginary=4;

        System.out.println("两个复数相乘得："+c1.mul(c2));
        c1.real=2;
        c1.imaginary=4;

        System.out.println("两个复数相除得："+c1.div(c2));
    }
}
class Complex
{
    double real;
    double imaginary;
//最后以字符串输出的格式：
//1.虚部为正值时，实部+"+"+虚部+"i" 2.虚部为0时，只有实部，即实部+"" 3.虚部为负值时，实部+""+虚部+"i"

    // 加法，减法：直接实部加减实部，虚部加减虚部
    String add(Complex c)
    {
        if(imaginary+c.imaginary>0)
            return (real=real+c.real)+"+"+(imaginary=imaginary+c.imaginary)+" i";
        else if(imaginary+c.imaginary==0)
            return (real=real+c.real)+"";
        else
            return (real=real+c.real)+""+(imaginary=imaginary+c.imaginary)+" i";
    }
    String sub(Complex c)
    {
        if(imaginary-c.imaginary>0)
            return (real=real-c.real)+"+"+(imaginary=imaginary-c.imaginary)+" i";
        else if(imaginary-c.imaginary==0)
            return (real=real-c.real)+"";
        else
            return (real=real-c.real)+""+(imaginary=imaginary-c.imaginary)+" i";
    }
// 乘法的公式：(a+bi)*(c+di) = a*c + bi*c + a*di + bi*di = a*c + (b*d)(i^2) + (b*c+a*d)i

    // 注：此处的i^2直接赋值-1，即 return a*c-b*d+(b*c+a*d)i
    String mul(Complex c)
    {
        if(imaginary*c.real+real*c.imaginary>0)
            return (real*c.real)-(imaginary*c.imaginary)+"+"+(imaginary*c.real+real*c.imaginary)+" i";
        else if(imaginary*c.real+real*c.imaginary==0)
            return (real*c.real)-(imaginary*c.imaginary)+"";
        else
            return (real*c.real)-(imaginary*c.imaginary)+""+(imaginary*c.real+real*c.imaginary)+" i";
    }
// 除法的公式：(a+bi)/(c+di) = (a+bi)*(c-di) / c^2+d^2

    // 注：在乘法的基础上得到格式A+Bdi，再进行A /c^2+d^2，B /c^2+d^2 + "i"
    String div(Complex c)
    {
        if(imaginary*c.real-real*c.imaginary>0)
            return ((real*c.real)+(imaginary*c.imaginary))/(c.real*c.real+c.imaginary*c.imaginary)+"+"+(imaginary*c.real-real*c.imaginary)/(c.real*c.real+c.imaginary*c.imaginary)+" i";
        else if(imaginary*c.real-real*c.imaginary==0)
            return ((real*c.real)+(imaginary*c.imaginary))/(c.real*c.real+c.imaginary*c.imaginary)+"";
        else
            return ((real*c.real)+(imaginary*c.imaginary))/(c.real*c.real+c.imaginary*c.imaginary)+""+(imaginary*c.real-real*c.imaginary)/(c.real*c.real+c.imaginary*c.imaginary)+" i";

    }
}
